v_therussian

Been meaning to revive this

So tell me again, how does the CDV work and why would the clutch burn up if you do a delete?

From what I have read, CDV is largely an unnecessary part that delays the application of the clutch. From what I can figure out - and this is really where things get blurry for me - CDV works when you "drop" the clutch by delaying the application of the clutch. In real life though, it seems to only get in the way when you want to shift quicker, by intervening and delaying the "clutching". So what you are saying is deleting the CDV will burn the clutch faster because it would result in more wear to the clutch? I shift sloppy sometimes in daily driving - I don't wanna burn the clutch by accidentally dropping the clutch in traffic or not rev-matching or smth

Krozi

Yea I'm not too sure about this...that's just what I heard a while ago...not quite sure about the physics behind it.

sportzfan76

Actually the CDV delete was the 1st planned mod for my E60 back when i first got the car. I had researched the Mod, chosen a vendor, etc...
20+ mods later - still no CDV delete

jm545i

The risk isn't "burning the clutch" with the CDV delete, the issue is simply the potential for excess drivetrain shock, and therefore the risk of stuff breaking, if you're constantly doing 6k clutch drops in your $70,000 worth of fine German engineering. As you say, clutch slippage, and therefore clutch wear, will likely be somewhat less under many driving situations with the CDV valve removed. I'm a strong supporter of getting rid of it - made a noticeable difference in the way my car shifts and feels. That said, if you loan your car to someone else who likes to impersonate John Force while driving your car, I'd recommend leaving it in.

porsche911targa

I hope you guys know that in today's modern cars this technique is absolutely unnecessary. The heel and toe technique was born out of necessity before transmissions had syncros. If you want to do it just for the fun of it or for nostalgia's sake, fine, but modern cars will probably experience less wear by not using the technique.

jm545i

Only if you're bad at it.

KAF

At last a sensible comment.

Krozi

Both of you don't know what you're talking about.
You mean double clutching.

Bimmerchop69

Ok so. Just throwing it out there. Why do the E60 545/550 clutches have such a soft pedal feel? I feel like I don't feel the clutch engaging so when doing a spirited launch I tend to burn more clutch and clutch engages too instantly with out a gradual engagement. I hope I am describing this right. Anyway in comparison, I previously owned a 350hp Nissan 240sx with a competition stage 5 clutch. Very heavy pedal feel but very predictable when clutch engages. Ok well enough said.

v_therussian

So the only way to damage is mis-matching rpms, basically? Like dropping the clutch from 0 at high rpm etc? What about a mis-matched shift during highway driving? Or during track driving?

Heel and toe is every bit as necessary as you say it is not. It all depends on how you drive, but even with rev-matching from the car, I rev-match way quicker and know what I need to do better than the car does. That's the reason we drive a manual. What did you think, we got it for fuel economy?

Then there's that

I'm pretty sure that the vague engagement is a problem that results from the clutch delay valve (CDV).

As for the light pedal - I actually like it. My friend has a 1999 M3 vert with a clutch as hard as a rock, and driving that thing is a PITA during anything, but the most spirited driving. I use my car to commute occasionally and drive it in city traffic, so having a lighter clutch pedal is actually great for me. Anyway, can't you calibrate it to an extent?